Submarine signaling apparatus



Feb. l, 1949. l H. BENioFF 2,460,274

-SUBMARIAE SIGNALING APPARATUS Filed Deo. 9, 1942 s sheets-sheet 1 1N VEN TOR.

FIG' 2 HUGO BENIOFF Feb. 1949. H. BENIOFF .SUBMINE SIGNALING .APPARATUS 3 Sheets-Sheet 2 Filed Deo. 9, 1942 Feb. l, 1949. H. BENxoFF VSUBMARINE SIGNALING APPARATUS s sheets-sheet 5 Filed Dec. 9, 1942 INVENTOR. HUGO BENIOFF www Patented Feb. l, 1949 snsnamnasicmmnc APPARATUS Hugo Benio', 'Pasadena, Calif.; assig'nor, by mesne assignment-s, to Submarine Signal Cornpany, Boston, Mass., a corporation of Delaware Application 'December 9, 1942, Serial No. 468,435

4 Claims. (Cl. lill-0.5)

The presen-t invention l'relates to apparatusfor acoustic signaling `Aand reception, and more particularly to the art of'signaling with the vuse of high frequency sound vibrations near and above the 'audible range -of frequenc'y. Y

The invention lnds particular application in the art of submarine signaling vas a means -for determining the direction of a sound source, or for 'transmission in a given direction.

The present invention fuses a sound reflector e at .the focus -o'f 'which -is api'ck-up unit of -a 'type particularly adaptable to receive the Waves rer'lected to it 1by the reflector.

.The invention is 'particularly adaptable for use bd substantially sound transparent for the sound waves iinpinging against it. For this purpose sound transparent rubber or some other Vmaterial such as seine suitable plastic may be used. "Preferably the joint between the flange l and the front cover '9 or shell vis made so that a continueus smooth surface is provided between the cuter surface 'of the sector il and that of the vcover A9. The Vback `cover or hemisphere 3 is preferably lined on 'the inside with a lining il; of some good sound-reiiectinor material as, for instance, cork or linoleuin or the like, and the outside With some soundabsorbing and protective material such, for instance, as a soft rubber covering l l overboard of a vessel or when projected through 1.3 which -will help to protect the metal shell 3 from the skinnfthe vessel. 'For this purpose the redents. Cck may well be used on both sides of nector is venclosed in a spherical housing which the shell 3. isfsupported by a shaft by'wh-ich the 'Whelehouse Mounted. and supported within the spherical ing 'mav be rotated. The reflector itself Yis shell formed by the elements described there is mounted'ihfsuch .away so that 'the desired ldirecgf) provided a reiiector '-i which may take the form tion of the reflector is Y:preserved even .though the ci a parabola of revolution or some such similar shaft may be inclined at varying angles. For suriace. This reector is provided at its edge thispurpose-a knife-edge support is preferable with a turned lip or rirn i3 extending all the to "a bearing surface for maintaining the reflector way around the reflector. This rim is provided at positioned in the desireddirection. 5 opposite 'ends of one diameter with perfoiations Other features ofthe presen-t invention reside er holes l? by which the reflector is supported.' in .part in the construction Vand arrangements of The reflector l2 is covered on 'both sides Withthin the elements rmaking Aup the apparatus Iand will layers of cork i5 and lf3 to provide a good re be more ful-ly and `readily understood from the iiecting surface and to prevent vibration being SDSCCS'OD deSCIibifng an `embodiment of the 30 picked up by the reflector vitself so that it will invention in connection with the drawings in act simpl-y as a reile'ctor for the energy which which Fig. l shows an lelevation -of the invention iinpinges vagainst it. with parts in section; Figs. 2 and 2a show details The periorations Vl by which the reflector is oi Fig. l; Fig. 3 shows a further detail of a modi supported are lined with a sleeve i8 made out of iication cf the sound pickup unit shown in Fig. l; 35 fabriclakelite element or other suitablematerial Fig. 4 shows a section on the line li-ll of Fig. 3; which also provides a durable bearing surface Fig. 5 shows a section on the line 5 5 of Fig. 3; under corrosive conditions such as sea water. Fig. 6 shows a detail for the support of the pickup This sleeve is fastened through a flange I 3 on unit of Fig. 1; and Fig. 'l shows a detail of the oneV side of the lip i3 and the other side by a' support for the spherical unit. 40 ciampin-g plate at. lThe sleeve i8 is shaped as In the drawings there is provided a spherical indicated in Fig. 2c with an opening with vtwo shell l which may be lled With `any V`liquid or straight sides 2l and 22 inclined to each other sound-conveying medium ll. The `spherical .shell and coming together at a vertex 23, The opencomprises preferably a metallic back half lor ing is arched over at the top as indicated l-by heini-'spherical portion 3 which may be made :out 45 the curve VIl-13. of any suitable metal plate such, for instance, as The .supporting sector Yor band 'il is pivoted aluminum or stainless steel. At 4the peripheral with 5a perforation 25 through which a projecting diameter 'of this half shell there is a supporting shaft 25 extends. This shaft has at its end a belt 4 or sector extending all the Way around rthe plate 52'? 'which is held tightly to the band or hemisphere. 'On one side this belt is joined by o() sector l by 'means of screws 2g. The vshaft 22E suitable means as, for instance, a row lof screws 5, 5 to the back shell 3, and on 'the other side the belt has a long ange 'l Vto which is cemented around its peripheral edge il, a rubber hemisphere 9 01"' some other suitable material which must -be as it extends inwardly through the band -l is provided with a knife-edge element 29, the knifeedge Sli of which rests in the vertex 23 formed b v the two straight sides -2 l 22 ofthe supporting sleeve i3. The suppor-tingsleeve i8 .must have such a surface that the knife-edge element 29 can freely be pivoted in it.

The spherical shell is supported in the band 4 as indicated by Fig. 7. This support has its axis in a direction perpendicular to the plane in which the section of Fig. l is shown so that if the shaft I4 is held in a vertical direction, the axis of the parabola will be horizontal. To provide equilibrium for the reector and the receiving unit mounted with it, the parabola may be weighted at the bottom by lead or other suitable means as indicated at 3i. The reflector is so mounted that it may swing for a considerable arc about its horizontal pivot. Its motion is prevented beyond a given amount by stops 32 and 33 suitably placed on the inside of the shell in such a way that as the reflector swings, it will hit against these stops. The angular position of these stops is such that the reflector will be stopped before the sides of the knife-edge 29 lie against the inclined surfaces ZI and 22 in the swing of the reiector.

The sound collected by means of the reflector I2 is reflected to the hydrophone unit 34 mounted at the focus and supported in a centrally located opening in the disc 35 which, in turn, is held by a frame made up of supporting brackets 36, 36, 35, fastened at one end to the plate 35 and at the other end to the edge or lip I3 of the parabola. The plate 35 and the hydrophone unit 34 are completely lined on their back faces with a soundreflecting cork layer 3'?, or other reflecting layer of material to reflect the sound direct from sources and thereby prevent it from exciting the hydrophone. Without the plate 35 covered as described, sound waves in the vicinity of the hydrophone would be picked up by the receiving element of the hydrophone and be made to indicate in the system. In this manner the directivity ofthe receiving unit would be impaired. The action of the plate 35 in its covered state is to reect such sound waves as might otherwise affect the hydrophone away from the hydrophone. This action eliminates sounds coming from directions other than that in which the reflector is pointed and thereby makes the unit more highly directive and provides a greater ratio of sound energy from the required direction to that coming from un- Wanted directions.

The bars or brackets 36, which are fastened at one end, as indicated in Fig. 6, by screws 38 to the disc 35, are bent over the lip I3 and fastened in their extensions 39 to the edge or lip of the reflector. The receiving unit 34 is mounted With its receiving diaphragm at right angles to the direction of the axis of the reiiector and facing the reflector. This hydrophone is shown more in detail in Figs. 3, 4, and 5. The only difference between the units shown in Figs. l and 3 is that in the latter figure the cable connections are taken out at the end of the casing instead of at the side of the casing as shown in Fig. l.

The hydrophone of Fig. 3 is made of a heavy casing 40 preferably of metal which has a recess 4I to receive the operating elements of the unit. The unit otherwise comprises a cover member 42 which is made with a heavy outer ring 43 fitting against the face ef the side wall 44 of the casing and an inner recessed thin diaphragm 45 which has a groove cut around its periphery forming a thin compliance web 46 which joins the central lvibratory diaphragm 'i5 to the heavy supporting ring t3.

The diaphragm is clamped to the casing by means of screws 41 spaced around the periphery of the supporting ring as indicated in Fig. 5. The casing is made watertight by the usual means indicated here by a rubber gasket 48 seated in the wall 44 of the heavy casing. Joined to the diaphragm and formed as an integral part of it is a thin cylindrical shell 49 of magnetostrictive material which extends from the rear of the diaphragm at or near the edge of the compliance web 46 but on the inside of the casing which is not exposed to the water medium. This cylindrical shell has at its end a heavy ring element 50 which is threaded at the inside at 5I to receive a cylindrical element 52 which is recessed at 53 on its inside face to receive the permanent magnet 54 which is retained tightly within the Y recess 53 in a. forced fit joint or by some other suitable means. The permanent magnet 54 has its end surface 55 parallel to the inside of the diaphragm member 45 and closely adjacent to it. Surrounding the cylinder 49 is a coil form 56 which at its front end has an outwardly extending flange 51 seated in the heavy rim 43 so that the coil is held outside of the vibrating portion of the diaphragm and will not therefore interfere with it. The coil form carries a coil 58 which is energized by the vibrations of the magnetostrictive cylinder 49.

The end surface of the heavy ring element 50 rests in a shoulder 5S at the bottom of the casing and is cemented in place by a layer of cement 60 in order to provide acoustic contact. A Bakelite disc 6I is fastened at the rear face of the cylindrical plug or threaded member 52 and this disc extends into a recess 62 extending from the back of the casing through which the connecting cable 63 passes. A watertight joint is made for this cable by means of a suitable stuffing box 64. The leads from the cable passing through holes in the Bakelite disc BI are connected through the grooves 65 and 66 in the heavy ring 50 to connect to the coil 58.

The cover member with its heavy metal ring 43 and its central metal vibratory diaphragm 45 as well as the magnetostrictive cylindrical element 49 and the heavy metal ring 50 may be and are preferably all one piece of material, and in the present modification of Fig. 3 are therefore of magnetostrictive material with the cylindrical threaded member 52 of magnetic material and the member 54 a permanent magnet.

In the operation of the device above described, the Whole apparatus may be lowered into the water and rotated on its shaft I4. The hydrophone will receive sound approaching in the direction of the axis of the reflector and will not receive sounds approaching from other directions. The sound which passes through the opening between the central baille and the edge of the reflector, if at angles inclined to the axis of the reflector, `will not come to a focus on the receiving diaphragm 45, but will be reflected outward from the reflector through the opening between the edge and the baille. The sound approaching the reflector in directions substantially parallel to the axis of the reflector will all be refiected and focussed to the diaphragm and will therefore add up to increase the sound intensity approaching from the direction of the axis of the reflector.

If the device is installed upon a moving vessel in which the shaft I4 does not retain its vertical position, then the pivoting of the reflector which itself carries the receiving unit makes it possible for the axis of the reflector always to be directed horizontally. v

Having now described my invention, I claim:

1. An underwater directional, compressienal. wave signaling device adapted to be projected into the Water comprising, in combination, a hollow spherical shell adapted to be filled With a wave transmitting medium and having a front half formed o a wave transmitting material and a rear half formed of a Wave reflecting material, a concave Wave reflector shaped to bring incldent plane waves to a focus substantially at a point, positioned Within said shell With its outer circumference bounded substantially at the junction vof the two halves thereof and With the cencave face facing toward said Wave transmitting half, said point being suiciently close to said reiector t-o be contained Within said shell whereby a Wave transducer may be placed Within said shell at said point of focus.

2. An underwater directional compressional Wave signaling device adapted to be projected into the water comprising, in combination, a hollow spherical shell adapted to be illed 'with a Wave transmitting medium and having a front half formed of a Wave transmitting material and a rear half formed of a Wave reflecting material, a concave Wave reector shaped in the form of a parabola of revolution positioned Within said shell with its outer circumference bounded substantially at the junction of the two halves thereof and with the concave face facing toward said wave transmitting half, the focal point being sufficiently close to said reflector to be contained Within said shell, whereby a Wave transducer may be placed Within said shell at said focal point.

3. A device as set forth in claim 1 wherein the reflector is pivotally mounted in said shell at tWo diametrically opposed points on a generally horizontal line and is weighted at a point below said line to maintain the signalling axis thereof substantially horizontal during tilting of sai sphere about said line.

4. A device as set forth in claim 1 wherein said wave transmitting material is rubber, said Wave reflecting material includes a rigid metal hernispherical shell, and said housing is iilled with a Wave transmitting fluid to maintain the spheri cal shape thereof.

HUGO BENIOF'F.

REFERENCES L'TED The following references are of record in the nie of this patent:

UNITED STATES PATENTS Number Name Date 768,573 Mundy Aug. 23, 1904 1,051,543 Blake Jan. 28, 1913 1,345,717 Thomas July 6, 1920 1,461,220 Moore July l0, 1923 1,464,103 Nash Aug. 7, 1923 1,471,547 Chilowsky et al. Oct. 23, 1923 1,836,397 Bieber Dec. 15, 1931 2,049,586 Hanson et al Aug. 4, 1936 2,153,571 Kallmeyer Apr. 11, 1939 2,155,163 Gerlach Apr. 18, 1939 2,228,024 Abrahams Jan. 7, 1941 FOREIGN PATENTS Number Country Date 395,081 Great Britain July 13, 1933 

